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result(s) for
"Vishwanath, Prashanth"
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Screening fructosamine-3-kinase (FN3K) inhibitors, a deglycating enzyme of oncogenic Nrf2: Human FN3K homology modelling, docking and molecular dynamics simulations
2023
Fructosamine-3-kinase (FN3K) is involved in the deglycation of Nrf2, a significant regulator of oxidative stress in cancer cells. However, the intricate functional aspects of FN3K and Nrf2 in breast cancers have not been explored vividly. The objectives of this study are to design the human FN3K protein using homology modeling followed by the screening of several anticancer molecules and examining their efficacy to modulate FN3K activity, Nrf2-mediated antioxidant signalling. Methods pertinent to homology modeling, virtual screening, molecular docking, molecular dynamics simulations, assessment of ADME properties, cytotoxicity assays for anticancer molecules of natural/synthetic origin in breast cancer cells (BT-474, T-47D), and Western blotting were used in this study. The screened anticancer molecules including kinase inhibitors of natural and synthetic origin interacted with the 3-dimensional structure of the catalytic domain in human FN3K protein designed through homology modeling by significant CDOCKER interaction energies. Subsequently, gefitinib, sorafenib, neratinib, tamoxifen citrate, and cyclosporine A enhanced the expression of FN3K in BT-474 cell lines with simultaneous alteration in Nrf2-driven antioxidant signalling. Oxaliplatin significantly downregulated FN3K expression and modulated Nrf2-driven antioxidant signalling when compared to cisplatin and other anticancer drugs. Hence, the study concluded the potential implications of existing anticancer drugs to modulate FN3K activity in breast cancers.
Journal Article
Evaluating the Antimicrobial and Anti-Hemolytic Activity of Synthesized Pseudopeptide against Leptospiral Species: In Silico and In Vitro Approach
by
Elbehairi, Serag Eldin I.
,
Shivamallu, Chandan
,
Jain, Anisha S.
in
ABC transporters
,
Amino acids
,
Animals
2023
Bacterial infections are one of the leading causes of morbidity, mortality, and healthcare complications in patients. Leptospirosis is found to be the most prevalent, re-emergent, and neglected tropical zoonotic disease worldwide. The adaptation to various environmental conditions has made Leptospira acquire a large genome (~4.6 Mb) and a complex outer membrane, making it unique among bacteria that mimic the symptoms of jaundice and hemorrhage. Sph2 is another important virulence factor that enhances hemolytic sphingomyelinase—capable of moving inside mitochondria—which increases the ROS level and decreases the mitochondrial membrane potential, thereby leading to cell apoptosis. In the present study, 25 suspected bovine serum samples were subjected to the Microscopic Agglutination Test (MAT) across the Mysuru region. Different samples, such as urine, serum, and aborted materials from the confirmed MAT-positive animals, were used for isolation and genomic detection by conventional PCR targeting virulence gene, Lipl32, using specific primers. Further, in vitro and in silico studies were performed on isolated cultures to assess the anti-leptospiral, anti-hemolytic, and sphingomyelinase enzyme inhibition using novel pseudopeptides. The microdilution technique (MDT) and dark field microscope (DFM) assays revealed that at a concentration of 62.5 μg/mL, the pseudopeptide inhibited 100% of the growth of Leptospira spp., suggesting its efficiency in the treatment of leptospirosis. The flow cytometry analyses show the potency of the pseudopeptide against sphingomyelinase enzymes using human umbilical vein endothelial cells (HUVECs). Thus, the present study demonstrated the efficacy of the pseudopeptide in the inhibition of the growth of Leptospira, and therefore, this can be used as an alternative drug for the treatment of leptospirosis.
Journal Article
evolution of N-glycan-dependent endoplasmic reticulum quality control factors for glycoprotein folding and degradation
by
Samuelson, John
,
Vishwanath, Prashanth
,
Cui, Jike
in
alpha-mannosidase
,
Animals
,
Biochemistry
2007
Asn-linked glycans (N-glycans) play important roles in the quality control (QC) of glycoprotein folding in the endoplasmic reticulum (ER) lumen and in ER-associated degradation (ERAD) of proteins by cytosolic proteasomes. A UDP-Glc:glycoprotein glucosyltransferase glucosylates N-glycans of misfolded proteins, which are then bound and refolded by calreticulin and/or calnexin in association with a protein disulfide isomerase. Alternatively, an α-1,2-mannosidase (Mns1) and mannosidase-like proteins (ER degradation-enhancing α-mannosidase-like proteins 1, 2, and 3) are part of a process that results in the dislocation of misfolded glycoproteins into the cytosol, where proteins are degraded in the proteasome. Recently we found that numerous protists and fungi contain 0-11 sugars in their N-glycan precursors versus 14 sugars in those of animals, plants, fungi, and DICTYOSTELIUM: Our goal here was to determine what effect N-glycan precursor diversity has on N-glycan-dependent QC systems of glycoprotein folding and ERAD. N-glycan-dependent QC of folding (UDP-Glc:glycoprotein glucosyltransferase, calreticulin, and/or calnexin) was present and active in some but not all protists containing at least five mannose residues in their N-glycans and was absent in protists lacking Man. In contrast, N-glycan-dependent ERAD appeared to be absent from the majority of protists. However, Trypanosoma and Trichomonas genomes predicted ER degradation-enhancing α-mannosidase-like protein and Mns1 orthologs, respectively, each of which had α-mannosidase activity in vitro. Phylogenetic analyses suggested that the diversity of N-glycan-dependent QC of glycoprotein folding (and possibly that of ERAD) was best explained by secondary loss. We conclude that N-glycan precursor length has profound effects on N-glycan-dependent QC of glycoprotein folding and ERAD.
Journal Article
Continuous evolution of Bacillus thuringiensis toxins overcomes insect resistance
by
Badran, Ahmed H.
,
Malvar, Thomas
,
Vishwanath, Prashanth
in
631/181/735
,
631/61/447
,
Amino Acid Sequence
2016
The
Bacillus thuringiensis
δ-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. Here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein–protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest
Trichoplusia ni
(TnCAD) that is not natively bound by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (dissociation constant
K
d
= 11–41 nM), kill TnCAD-expressing insect cells that are not susceptible to wild-type Cry1Ac, and kill Cry1Ac-resistant
T. ni
insects up to 335-fold more potently than wild-type Cry1Ac. Our findings establish that the evolution of Bt toxins with novel insect cell receptor affinity can overcome insect Bt toxin resistance and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects.
Phage-assisted continuous evolution (PACE) rapidly evolves
Bacillus thuringiensis
toxins through more than 500 generations of mutation, selection, and replication to bind a receptor expressed on the surface of insect-pest midgut cells.
Beating Bt resistance in insect pests
The emergence of insects resistant to
Bacillus thuringiensis
δ-endotoxins (Bt toxins) is threatening to reduce the effectiveness of this system in crops engineered to carry these insecticidal proteins. David Liu and colleagues have used phage-assisted continuous evolution (PACE) selection to rapidly evolve high-affinity protein–protein interactions, and applied the system to evolve Bt toxin variants that kill insects through binding a new insect gut cell protein target — a cadherin-like receptor from the insect pest
Trichoplusia ni
. The modified Bt toxins are shown to overcome Bt toxin resistance and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects.
Journal Article
Screening fructosamine-3-kinase
2023
Fructosamine-3-kinase (FN3K) is involved in the deglycation of Nrf2, a significant regulator of oxidative stress in cancer cells. However, the intricate functional aspects of FN3K and Nrf2 in breast cancers have not been explored vividly. The objectives of this study are to design the human FN3K protein using homology modeling followed by the screening of several anticancer molecules and examining their efficacy to modulate FN3K activity, Nrf2-mediated antioxidant signalling. Methods pertinent to homology modeling, virtual screening, molecular docking, molecular dynamics simulations, assessment of ADME properties, cytotoxicity assays for anticancer molecules of natural/synthetic origin in breast cancer cells (BT-474, T-47D), and Western blotting were used in this study. The screened anticancer molecules including kinase inhibitors of natural and synthetic origin interacted with the 3-dimensional structure of the catalytic domain in human FN3K protein designed through homology modeling by significant CDOCKER interaction energies. Subsequently, gefitinib, sorafenib, neratinib, tamoxifen citrate, and cyclosporine A enhanced the expression of FN3K in BT-474 cell lines with simultaneous alteration in Nrf2-driven antioxidant signalling. Oxaliplatin significantly downregulated FN3K expression and modulated Nrf2-driven antioxidant signalling when compared to cisplatin and other anticancer drugs. Hence, the study concluded the potential implications of existing anticancer drugs to modulate FN3K activity in breast cancers.
Journal Article
Evaluating the Antimicrobial and Anti-Hemolytic Activity of Synthesized Pseudopeptide against ILeptospiral/I Species: In Silico and In Vitro Approach
2023
Bacterial infections are one of the leading causes of morbidity, mortality, and healthcare complications in patients. Leptospirosis is found to be the most prevalent, re-emergent, and neglected tropical zoonotic disease worldwide. The adaptation to various environmental conditions has made Leptospira acquire a large genome (~4.6 Mb) and a complex outer membrane, making it unique among bacteria that mimic the symptoms of jaundice and hemorrhage. Sph2 is another important virulence factor that enhances hemolytic sphingomyelinase—capable of moving inside mitochondria—which increases the ROS level and decreases the mitochondrial membrane potential, thereby leading to cell apoptosis. In the present study, 25 suspected bovine serum samples were subjected to the Microscopic Agglutination Test (MAT) across the Mysuru region. Different samples, such as urine, serum, and aborted materials from the confirmed MAT-positive animals, were used for isolation and genomic detection by conventional PCR targeting virulence gene, Lipl32, using specific primers. Further, in vitro and in silico studies were performed on isolated cultures to assess the anti-leptospiral, anti-hemolytic, and sphingomyelinase enzyme inhibition using novel pseudopeptides. The microdilution technique (MDT) and dark field microscope (DFM) assays revealed that at a concentration of 62.5 μg/mL, the pseudopeptide inhibited 100% of the growth of Leptospira spp., suggesting its efficiency in the treatment of leptospirosis. The flow cytometry analyses show the potency of the pseudopeptide against sphingomyelinase enzymes using human umbilical vein endothelial cells (HUVECs). Thus, the present study demonstrated the efficacy of the pseudopeptide in the inhibition of the growth of Leptospira, and therefore, this can be used as an alternative drug for the treatment of leptospirosis.
Journal Article
Screening fructosamine-3-kinase (FN3K) inhibitors, a deglycating enzyme of oncogenic Nrf2: Human FN3K homology modelling, docking and molecular dynamics simulations
2023
Fructosamine-3-kinase (FN3K) is involved in the deglycation of Nrf2, a significant regulator of oxidative stress in cancer cells. However, the intricate functional aspects of FN3K and Nrf2 in breast cancers have not been explored vividly. The objectives of this study are to design the human FN3K protein using homology modeling followed by the screening of several anticancer molecules and examining their efficacy to modulate FN3K activity, Nrf2-mediated antioxidant signalling. Methods pertinent to homology modeling, virtual screening, molecular docking, molecular dynamics simulations, assessment of ADME properties, cytotoxicity assays for anticancer molecules of natural/synthetic origin in breast cancer cells (BT-474, T-47D), and Western blotting were used in this study. The screened anticancer molecules including kinase inhibitors of natural and synthetic origin interacted with the 3-dimensional structure of the catalytic domain in human FN3K protein designed through homology modeling by significant CDOCKER interaction energies. Subsequently, gefitinib, sorafenib, neratinib, tamoxifen citrate, and cyclosporine A enhanced the expression of FN3K in BT-474 cell lines with simultaneous alteration in Nrf2-driven antioxidant signalling. Oxaliplatin significantly downregulated FN3K expression and modulated Nrf2-driven antioxidant signalling when compared to cisplatin and other anticancer drugs. Hence, the study concluded the potential implications of existing anticancer drugs to modulate FN3K activity in breast cancers.
Journal Article
Use of sustainable chemistry to produce an acyl amino acid surfactant
by
Somasundaran, Ponisseril
,
Reznik, Gabriel O
,
Castle, Andrew B
in
Amino Acid Sequence
,
Amino acids
,
analogs & derivatives
2010
Surfactants find wide commercial use as foaming agents, emulsifiers, and dispersants. Currently, surfactants are produced from petroleum, or from seed oils such as palm or coconut oil. Due to concerns with CO₂ emissions and the need to protect rainforests, there is a growing necessity to manufacture these chemicals using sustainable resources In this report, we describe the engineering of a native nonribosomal peptide synthetase pathway (i.e., surfactin synthetase), to generate a Bacillus strain that synthesizes a highly water-soluble acyl amino acid surfactant, rather than the water insoluble lipopeptide surfactin. This novel product has a lower CMC and higher water solubility than myristoyl glutamate, a commercial surfactant. This surfactant is produced by fermentation of cellulosic carbohydrate as feedstock. This method of surfactant production provides an approach to sustainable manufacturing of new surfactants.
Journal Article
Continuous evolution of B. thuringiensis toxins overcomes insect resistance
2016
The Bacillus thuringiensis δ-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. We developed a phage-assisted continuous evolution (PACE) selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest Trichoplusia ni (TnCAD) that is not natively targeted by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (Kd = 11–41 nM), kill TnCAD-expressing insect cells that are not susceptible to wild-type Cry1Ac, and kill Cry1Ac-resistant T. ni insects up to 335-fold more potently than wild-type Cry1Ac. Our findings establish that the evolution of Bt toxins with novel insect cell receptor affinity can overcome Bt toxin resistance in insects and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects.
Journal Article
Phylogeny of translation-associated proteins and novel controls for RNA expression analysis
2006
Information transfer in biological systems is a complex set of events that leads from DNA through many intermediates to functioning proteins. This research focuses on two of its aspects: cellular translation and transcription. I have carried out a detailed phylogenetic analysis of proteins involved in translation. Cross-phylodomain sequence alignments of orthologous ribosomal proteins from Bacteria and Archaea show an unusual block structure with some blocks universal to both phylodomains while others are phylodomain-specific. Such block patterns seem to be a characteristic of the translational system. Surprisingly, the distinct blocks in ribosomal proteins do not correlate with any specific functional or structural feature including RNA or protein contacts. They may have some selective advantage in each phylodomain as seen from experiments swapping a bacterial block in L4 with a corresponding archaeal block. The presence of the universal blocks clearly implies common ancestry of the bacterial and archaeal translational systems, but the ubiquity of the phylodomain-specific blocks within each group argues for the presence of a single ancestor for each phylodomain that existed long after their common ancestor. A second project involves design and development of external RNA controls for microarray experiments that can provide more accurate measures of differentially expressed mRNA, which are the inputs to the translational system. \"Alien\" oligo sequences were designed not to be similar to any known or predicted open reading frames within an organism of interest. When used as probes, the alien oligos fail to cross-hybridize to mouse or human total RNAs and serve as useful negative controls. Synthetic RNA molecules produced by in vitro transcription of gene sequences formed by concatenating alien oligos linked to a T7 promoter and polyA tail function as in-spike controls. Alien sequences can also serve as universal in-spot references. When co-printed with gene-specific probes and hybridized with its reverse complement labeled with a third fluorophore, an alien sequence acts as an in-situ reference and provides a basis for indirect comparison. This allows for the study of gene transcription during multivariable or longitudinal microarray experiments that otherwise may be unworkable because of the inadequacy of traditional control procedures.
Dissertation